02lecture.pdf

Where are we nowBig Sixwhat we need to survive land minerals forests water food energyLandlimitations only 12 of total land can be used which amounts to 3 of earths surface can be used to grow food which is currently mostly being usedwin the second half of last century Asia SA Africa have transformed 200 mill hectares of habitat area into arable and croplandarable land per capita has gone down almost everywhereMineralsmineral extraction has doubled in 30 yrs between 1970 and 2000some minerals have peaked alreadyex silver and gold have15 years of extraction left copper has30 yrsalso most sites of mineral extraction have destroyed forest or farmlandForestsnot just a source of fuel fiber lumber they are the Earths lungs together w algae in the oceanmajor source of oxygen for the Earths atmospherealso source of water circulation as much as 50 of water that ends up in couds for rain has be transpired by forestsremove forests and you have desertthey build and protect top soil remove lose soil and minerals by erosionare major carbon sinks capturing storin